docker-compose command 'npm start' does not start react app automatically?

I am reasonably new to react application.

docker-compose command 'npm start' does not start react app automatically?

package.json:

"react": "^16.13.1",
    "react-dom": "^16.13.1",
    "react-scripts": "3.4.1"
    },
    "scripts": {
      "start": "react-scripts start",
      "build": "react-scripts build",
      "test": "react-scripts test",
      "eject": "react-scripts eject"
  },
    "eslintConfig": {

docker-compose:

.....:

  command: bash -c "npm start && nginx -g 'daemon off;' "

Log Output:

portals_1            | 
portals_1            | > myreact@0.1.0 start /~/~/myreact
portals_1            | > react-scripts start
portals_1            | 
portals_1            | ℹ ｢wds｣: Project is running at http://172.18.0.9/
portals_1            | ℹ ｢wds｣: webpack output is served from 
portals_1            | ℹ ｢wds｣: Content not from webpack is served from /~/~/myreact/public
portals_1            | ℹ ｢wds｣: 404s will fallback to /
portals_1            | Starting the development server...
portals_1            | 

At this point, docker container runs but react server does not. However if I bash into docker container

docker-compose exec portals bash

I check that port 3000 is still free. If I go to the directory and run npm start then react runs normally and everything is as expected.

Log Output: - You can now view myreact in the browser.

Local:            http://localhost:3000
On Your Network:  http://172.18.0.9:3000

Note that the development build is not optimized.
To create a production build, use npm run build.......

Why react application is not able to start normally from docker-compose?